Feed & Additive Magazine Issue 17 June 2022

ISSUE FOCUS FEED & ADDITIVE MAGAZINE June 2022 47 Furthermore, once a bird can no longer maintain its body heat balance, the birds spend more time resting and with wings aloft, water consumption increases, and feed intake decreases. Simultaneously, the bird’s blood flow is partially redirected from the body core to the periphery. Decreased blow flow to the internal organs—such as the gut—creates oxygen deprivation and reduces nutrient intake, and can increase gut permeability, thus creating a leaky gut. Under these conditions, pathogenic bacteria (such as E.coli and Clostridium perfringens) and their endotoxins (lipopolysaccharides or LPS) can traverse the gut wall and enter the bloodstream, potentially inducing fever, blood coagulation, decreased blood pressure, and eventually multiple organ failure and death. As a consequence, corticosterone release can increase which results in negative effects on both the thyroid gland and immune system, rendering the bird more susceptible to infection and negatively affecting bird performance. INTEGRATED EFFICIENT HEAT STRESS MANAGEMENT To protect the birds against heat stress, poultry producers outfit houses with proper equipment (e.g. sprinklers or foggers), implement appropriate feeding and nutritional strategies. To complete the picture, poultry producers are searching for additional cost-effective, sustainable solutions, especially under current cereal and energy (e.g. electricity) turbulent supply and price which heavily impact poultry production cost. Numbers of studies, conducted worldwide, have demonstrated that the premium-quality yeast postbiotic, Safmannan® (here after called “yeast postbiotic”) has the ability to decrease body temperature, modulate thyroid hormone and corticosterone secretions, preserve gut morphology and improve birds’ performance under different levels of heat stress. To avoid leaky gut, one of the frequent heat stress induced gut issues, it’s crucial to preserve tight junctions which are essential to intestinal barrier maintenance by tightly connecting epithelial cells together. A study was conducted in Japan recently to explore the effects of yeast postbiotic on poultry gut morphology preservation under severe acute heat stress. The expression levels of two gut tight junction proteins (ZO-1 and Claudin-5) were assessed under both normal conditions, and conditions of severe acute heat stress (THI of 32) with and without 250 g/t Safmannan® supplementation in broilers’ diet. In animals undergoing heat-stress, these protein levels nearly halved compared to controls, and thus could contribute to a leaky gut phenotype. Nutritional supplementation with the yeast postbiotic enabled the reversion of junction proteins to near negative control levels, indicating a return to normal gut integrity. A robust gut barrier will also reduce liquid loss from the bloodstream into the gut, as seen by drier feces. Heat stress can trigger proliferation of the enteropathogenic Clostridium perfringens bacteria in the poultry gut resulting in chronic inflammation and consequently poor production performance. A recent trial in the Middle East investigated the effects of adding 500 g/t Safmannan® in broilers’ feed inoculated with an infectious dose of Clostridium perfringens, under natural heat stress conditions. At day 30, supplemented birds demonstrated a 2-Log reduction Figure 1. Behavioral changes related to different level of THI (Adapted from Anses, Ploufragan and Manual of poultry diseases, Jeanne Brugère Picoux)

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